Objective. To review the diagnostic yield of flexible sigmoidoscopy in patients presenting with bright red rectal bleeding. Design. Retrospective study. Setting. University teaching hospital, Hong Kong. Subjects and methods. Patients who underwent flexible sigmoidoscopy between January 1995 and April 1996 for investigation of bright red rectal bleeding were recruited. The extent of the endoscopic examination, complications, and endoscopic findings were recorded. Results. A total of 1052 patients were included in the study. The mean length of endoscopic examination was 55 cm. There were no complications attributed to the procedure. Thirteen (1.2%) patients aged from 41 to 87 years were found to have malignant tumours that were not palpable on digital examination. All the tumours were moderately differentiated adenocarcinoma. Two patients had synchronous liver metastasis at presentation. Adenomatous polyps were detected in 81 (7.7%) patients, of whom 76 were older than 40 years. The majority of polyps were tubular adenomas associated with mild or moderate dysplasia. Other endoscopic findings included hyperplastic and juvenile polyps, proctocolitis, diverticulosis, irradiation colitis, ischaemic colitis, rectal ulcers, and infective colitis. The overall diagnostic yield was 21.1%. No mucosal lesion was detected by flexible sigmoidoscopy in 78.9% of patients in whom the rectal bleeding was due to either haemorrhoids or anal fissure. Conclusions. Cancer was detected in 1.2% and adenomatous polyps in 7.7% of patients with bright red rectal bleeding using flexible sigmoidoscopy. All cancers and 94% of adenomatous polyps were detected in patients older than 40 years. Flexible sigmoidoscopy appears to be a valuable initial investigation for bright red rectal bleeding in patients older than 40 years.published_or_final_versio
